The Public Availability calendar option in GP profiles

The option of making your availability public simply means that you allow your availability calendar to be viewed on a public URL, outside of a GPn login – so you could send it to an employer, for example. As a feature it should have no direct bearing on your opportunity to find locum work through the system. All practices suing GPn will be able to see your availability as long as you have set them as Visible to you in your Visibility tab.